The present disclosure relates to tin-based solder melt and aqueous tin-based plating bath compositions and methods of coating a metal substrate using the tin-based composition.
Tin-based solder compositions are commonly used in microelectronics production to bond electronic or hardware components together. Of particular relevance is the use of solder in connecting electronic components (such as a chip) onto a printed circuit board.
A persistent problem encountered in the use of tin-based solder processes is the occurrence of voids in the solder coat. Voids are highly undesirable particularly since they result in a non-uniform coating and can result in bond failure. The occurrence of such voids typically decreases over time and may eventually become absent during long term use of the solder. As a result, a currently known remedy is to modify the process by including a “break-in” period before the solder is used in production. During the break-in period, which typically lasts for 10 to 16 days, the solder bath is kept molten and optionally used to plate dummy objects. The presence of voids can be monitored during the course of the break-in period to establish the point in time when the solder bath exhibits an acceptably low void output for use in production.
As the current requirement for a lengthy break-in period results in higher cost and lower production efficiency, it poses a significant problem in current microelectronics manufacturing. For this reason, there would be a significant advantage in a soldering process that eliminates the need for a break-in process and that provides high quality solder coats free of voids from the outset.